In recent years, research on optical tomographic imaging systems (hereinafter referred to as “OCT: Optical Coherence Tomographs”) which visualize the depth structure of the inside of a biological body by making use of an interference effect of light has been advancing.
In particular, recently, from the fact that optical tomographic imaging systems are non-invasive to living bodies and have high resolving power, the optical tomographic imaging systems is not only used for tomographic imaging of eye retinas, but also be attempted to use for tomographic imaging of biological organs other than retinas, or other structures.
Under such circumstances, a polarization OCT system, which employs the optical tomographic imaging system combined with polarization detection, is known.
For example, such polarization OCT system delivers a light beam polarized at 45 degrees into a sample (an object to be measured) such as a biological organ, and combines a polarization beam reflected from the sample (hereinafter referred to as an “object-reflected polarization beam”) with reference light. The polarization OCT system is capable of imaging an internal structure of the sample by separating the combined light beam into each polarization component, i.e. vertical polarization and horizontal polarization, and by analyzing such components (see, for example, Patent Documents 1, 2 and 3).